It's even weirder than that: mention of the shell GUI is just the intro, later they proceed with implementing a facsimile of the Windows NT kernel in... TypeScript. Even for purely self-educational purposes, this pairing seems to be very counterproductive.
I agree that the title is misleading and should be changed. I also expected LG webOS.
The article's author has no claim to it and should remove the references to it. HN post title should be updated too.